为探究虎斑乌贼(Sepia pharaonis)喷墨对其行为、生长、存活及酶活的影响,采用单因子试验法,进行了喷墨虎斑乌贼(喷墨组)和未喷墨虎斑乌贼(对照组)的养殖比较试验,试验时间30d.研究结果表明,虎斑乌贼喷墨后会导致其体色泛白、活力下降,严重的会导致死亡;养殖30d后,对照组虎斑乌贼的存活率、增重率和特定生长率均显著高于喷墨组(P<0.05);特定生长率和增重率在试验时间≤10d时对照组显著高于喷墨组(P<0.05),随着养殖时间延长,2组无显著差异(P>0.05);喷墨组的抗氧化能力包括超氧化物歧化酶(SOD)活性、丙二醛(MDA)和谷胱甘肽(GSH)含量均显著高于对照组(P<0.05),但过氧化氢酶(CAT)却显著低于对照组(P<0.05);喷墨组的代谢酶包括谷丙转氨酶(GPT)和乳酸脱氢酶(LDH)的活性均显著高于对照组(P<0.05),但酸性磷酸酶(ACP)的活性却显著低于对照组(P<0.05).试验表明,虎斑乌贼喷墨不仅会导致其生长缓慢、存活率下降,并且会影响其体内相关酶的活性.

为探究苗种规格对虎斑乌贼(Sepia pharaonis)养殖效果的影响,进行了放养3种不同规格乌贼苗种(胴长分别为(4.09±0.15)、(5.25±0.48)和(6.16±0.19)cm)的养殖实验.结果表明:不同规格乌贼苗种的摄食量均波动上升,饵料系数随养殖时间逐渐降低,由8.00±1.01降至3.74±0.35.乌贼苗种的特定生长率先增加,在胴长6cm左右时达到峰值,后减少并稳定至4％左右.3种规格乌贼苗种养殖30d后的存活率分别为(88.50±0.88)％、(92.00±0.60)％、(93.83±0.34)％.大规格乌贼苗种的日均增重量、存活率显著(P<0.05)高于小规格乌贼苗种.综上所述,在虎斑乌贼养殖中苗种放养规格以胴长6 cm左右为宜.

为了加快虎斑乌贼产业化养殖进程,于2017年6月9日至9月9日在浙江象山来发水产育苗场的室内水泥池进行了虎斑乌贼规模化养殖试验.共放养人工繁育的虎斑乌贼苗种2000只(平均胴长为3.8 cm),放养初始密度50～60只/m2,起捕前密度5～8只/m2;养殖条件:水位80～120 cm,水温20℃ ～32℃、盐度22‰～33‰、pH 7.6～8.4,溶氧4.0 mg/L以上;每天投喂冰鲜小杂鱼虾2次,投饵量6％ ～18％;日换水1次,换水量80％ ～100％.结果表明:经90 d养殖,乌贼的体质量随养殖时间呈指数增长:W=10.718e0.045d,体质量为420～620 g,平均体质量为513 g;胴长随养殖时间呈线性增长:WL=0.1401d+3.1815,乌贼胴长达到15.3～18.6 cm,平均胴长为16.6 cm;养殖成活率达到61.5％,养殖平均饵料系数为4.36.表明虎斑乌贼是一种生长快、养殖周期短、经济效益高的养殖新品种,适合规模化养殖.

An experiment with single-factor design was conducted to investigate the effects of light intensity on growth and survival of cuttlefish (Sepia pharaonis). The specific growth rate, survival rate, oxygen consumption rate, ammonia excretion rate, lactic acid content in muscle, respiratory metabolic enzymes (including hexokinase, pyruvate kinase, and lactate dehydrogenase), supero-xide dismutase, and malondialdehyde in liver were measured in five constant light intensity treatments (10, 30, 50, 70, 90 μmol·m-2·s-1). The main results were as follows: The specific growth rate and survival rate remained steady initially and then decreased gradually with the increases of light intensity. There was no significant difference between groups 10 and 30 μmol·m-2·s-1, but they were significantly higher than those of the other groups. Exposed to light intensities of 10 and 30 μmol·m-2·s-1, the specific growth rates were (8.43±0.22)%·d-1 and (8.47±0.17)%·d-1, and the survival rates were (79.2±5.9)% and (80.0±4.9)%, respectively. Oxygen consumption rates and ammonia excretion rates increased first slowly and then sharply, and reached the maximum value when light intensity was 90 μmol·m-2·s-1, which was significantly higher than those of the other groups. Lactic acid content in muscle firstly decreased and then increased, with the minimum value at 30 μmol·m-2·s-1. The acid content of 10 μmol·m-2·s-1 was significantly lower than those of the other groups except 30 and 50 μmol·m-2·s-1. With the increases of light intensity, the activities of HK and PK in gills remained steady initially and then decreased gradually, and reached the highest level when exposed to 10 and 30 μmol·m-2·s-1, which were significantly higher than those of the other groups. LDH activity in muscle had the lowest level at the light intensity of 10 and 30 μmol·m-2·s-1, which was significantly lower than those of the other groups. SOD activity in liver firstly increased and then decreased, and reached the highest level ((104.93±4.17) U·mg-1 pro) when exposed to 70 μmol·m-2·s-1, which was significantly higher than those of the other groups. MDA content in liver first remained steady and then increased gradually, and reached the highest level ((5.06±0.35) nmol·mg-1 pro) when exposed to 90 μmol·m-2·s-1, which was significantly higher than those of the other groups. In conclusion, the optimum light intensities for growth, survival and metabolism of S. pharaonis were 10 and 30 μmol·m-2·s-1, beyond which S. pharaonis would be under stress. Therefore, sunproof measures should be taken to keep weak light condition in culture practice.

Several marine mollusks, including cephalopods (cuttlefish, squid, and octopus) and gastropods (e.g., sea hares), can release a colored ink secretion when chased by predators or stimulated. Ink release is part of a defensive response, but the threshold for the biochemical responses caused by stimulation is unknown. The present study aimed to reveal antipredator responses of cuttlefish, such as escaping via inking and/or jetting, and to investigate its biological and biochemical responses to continuous ink release. Results showed that the behavioral responses to continuous ink release mainly manifested as blazing body pattern changes. Cuttlefish escaped from predators covered by jetting/inking and warned the potential threats by displaying a unique body pattern. Moreover, persistent inking in the presence of an overt stimulus caused uncontrollable ink release from the ink duct/anal canal (loss of control). This study first verified the characteristics of the cuttlefish ink solution, prepared a standard curve of ink solution concentrations, and fitted the relationship function between the release frequency and the released ink weight. Biological statistics indicated that cuttlefish has the ability to continuously release ink (releasing ∼90% of the ink from the ink sac) and that the individuals adapted well during the recovery period. However, re-releasing ink would result in “overexploitation” and high mortality. Hexokinase (HK), pyruvate kinase (PK), and superoxide dismutase (SOD) activities, as well as malondialdehyde (MDA) concentration increased or remained stable in different tissues after releasing ink. The expression of heat shock protein 90 and arginine kinase (AK) were upregulated by stimuli in all tissues. Biochemical changes indicated that continuous inking not only consumed considerable energy but also damaged the tissues. In summary, cuttlefish released almost 90% of their ink for active defense against predators, and it took ∼30 days for the ink sac to be refilled, but “overexploitation” resulted in serious physiological damage. These findings will be helpful to further study the defense and ink release mechanisms and to consider animal health and welfare when using cephalopods as experimental animals and for aquaculture practices.

为了探讨氨氮对虎斑乌贼器官组织结构的影响,以体质量为(13.80±0.65)g的幼虎斑乌贼为对象,研究了氨氮胁迫对其肝脏、鳃和脑组织结构的影响.根据96 h的LC50实验结果设计5个梯度(0、1、3、6和12 mg/L)进行96 h的氨氮胁迫后,利用光学显微镜和透射电子显微镜观察其肝脏、鳃和脑组织结构.结果显示,在相同浓度的氨氮胁迫下,虎斑乌贼不同组织器官之间损伤程度存在差异,其中肝脏损伤的程度最大,对氨氮胁迫表现最敏感,其次是鳃组织和脑组织,组织器官损伤程度与氨氮浓度呈现正相关.氨氮胁迫浓度越大或胁迫时间越长,肉眼观察发现肝脏颜色越鲜红,肿胀和易糜烂程度越明显,可通过肉眼观察肝脏颜色和肿胀程度初步判断机体氨中毒程度;氨氮胁迫后,对肝脏和鳃组织造成较为严重的损伤,可能是虎斑乌贼氨中毒致死的原因.当氨氮高于或等于6 mg/L时胁迫96 h后,通过显微观察发现肝小叶轮廓模糊不完整、排列不紧密和胞浆疏松透明,大量的细胞核溶解,细胞出现空泡化,肝血窦扩张;通过电镜观察发现细胞核皱缩变形、核仁消失、线粒体嵴紊乱、线粒体空泡化、线粒体外室肿胀,高尔基体数量减少;显微观察发现鳃组织的泌氯细胞和上皮细胞核溶解,细胞出现空泡化、排列紊乱,鳃丝肿胀淤血、轮廓模糊不完整,并出现坏死脱落和缺损;通过透射电镜观察,发现细胞核皱缩、核膜破损和细胞核裂解,线粒体出现了皱缩变形、空泡化和不完整破损现象;观察脑组织的神经团和视叶,未发现脑组织的细胞有显著损伤.